Standard deviation

When Alfred Charles Kinsey was hired as an assistant professor of zoology at Indiana University in 1920, he began a two-decade study of the gall wasp, collecting over 1 million samples. He loved the gall wasp, he said, because each one was totally different from the others. In 1938, at the behest of curious students, he taught a course called “Marriage” that was designed to dispel the sexual myths that were confounding and frustrating young people. (“Is it true that oral sex can cause problems getting pregnant? Will excessive masturbation lead to impotence?”)

Kinsey gave the students what they wanted, and then some. Soon his students were taking a written questionnaire about their sex lives. Then he designed a 350-question interview process, and within two years Kinsey and colleagues were traveling across the country conducting thousands of interviews. They discovered that when it came to sex, each subject was totally different from the others.